Diabetes patients use some form of daily insulin therapy to maintain close control of their glucose levels. Infusion pump therapy is one preferred method. Infusion pump therapy occurs via an infusion cannula (i.e., an infusion needle or a flexible catheter) and requires an infusion pump. Infusion pump therapy offers the advantages of continuous infusion of insulin, precision dosing, and programmable delivery schedules.
The use of an infusion pump requires the use of a disposable component, typically referred to as an infusion set, tubing set, which administers insulin from a reservoir that is pumped into the skin of the user. An infusion set typically consists of a pump connector, a length of tubing, and a hub or base from which an infusion cannula extends. The base has an adhesive that attaches the base on the skin surface during use. The base, with the infusion cannula attached thereon, may be applied to the skin manually or with the aid of a manual or automatic insertion device.
There are many available types of infusion sets incorporating various types of infusion cannulas, including steel needle infusion sets and soft catheter sets. Soft catheter sets can be inserted into a patient with the aid of a steel introducer needle, which is later removed from the patient, leaving the soft catheter in place. The steel cannula infusion set utilizes a steel needle or cannula that is secured to the base.
An advantage of the steel cannula infusion sets is that the steel cannulas, due to their rigidity are less susceptible to kinking. Kinking occurs when the infusion cannula, be it rigid or soft, is unable to resist mechanical forces that may bend or twist the infusion cannula, resulting in a restricted flow of infusate exiting the catheter. Another advantage of a steel cannula infusion set is that the steel cannula pierces the patient's skin without the need for a separate introducer needle, as in soft catheter sets.
A steel cannula typically is protected by a disposable protective tube (typically made of plastic) that is attached to the base, surrounding the steel cannula, prior to use, and such attachment generally is not very secure. The user removes the disposable tube before the steel cannula is inserted into the user's skin. The protective tube is generally disposed of.
A steel cannula infusion set is illustrated in FIGS. 1-5
FIG. 1 illustrates a steel cannula infusion set 1 having a plastic fluid connector or hub 22 that is detachably attached to a plastic base 10, a fluid tubing set 28, and a plastic connector 26 which is attachable to a pump (not shown). The connector 26 includes an outer wall 262. The line set 20 includes the hub 22 and the fluid tubing set 28. The line set 20 is attached to or detached from the base 10, as illustrated in FIGS. 2 and 3.
FIG. 2 is a top view of the infusion set 1, illustrated with the hub 22 attached to the base 10. An adhesive pad 19 is attached to the base 10 and is configured to be attachable to the skin of the user. FIG. 3 illustrates a view of the infusion set 1, wherein the line set 20 is detached from the base 10. The base 10 includes an infusion adapter 14, to which the steel cannula 13 is attached.
FIG. 4 is a cross-sectional view of the infusion set 1, taken along lines 4-4 of FIG. 1, that more clearly illustrates how the infusate (insulin) is pumped into the steel cannula 13. The hub 22 of the line set 20 includes a hub port 25 that receives the fluid tubing set 28. The hub 22 includes a flow cannula 24. The base 10 includes a main base portion 12 and the adapter 14 includes a cylindrical lower portion 16, to which is attached the steel cannula 13, and a cylindrical inner wall portion 17 that is spaced apart from the lower portion 16. A pre-slit septum 18 encloses an upper portion of the adapter 14, when the hub 22 is not attached to the infusion base 10, as illustrated in FIGS. 3 and 5.
When the hub 22 is attached to the base 10, the flow cannula 24 penetrates the pre-slit septum 18 of the base 10 so that the steel cannula 13 is in fluid communication with the fluid tubing set 28, via channel 11. This allows the insulin from the pump (not shown) to flow from the fluid tubing set 28 into the steel cannula 13 and the insulin exits the distal opening or tip 131 of the steel cannula 13 into the patient.
FIG. 5 illustrates a cylindrical protector 30 attached to the base 10 to protect the steel cannula 13. Prior to use, the protector 30, which is form-fit in the base 10, is removed, and the protector 30, typically a tubular structure made of plastic, is disposed of.
A problem arises when a steel cannula infusion set is to be disposed. When the steel cannula 13 is removed from the user, which may be two or three days after initial insertion, the user may no longer have the disposable protector 30 or protective tube to cover the steel cannula 13 that may now contain bodily fluids. Even if the disposable protective tube 30 were available, since the attachment to the base 10 is not very secure, the protective tube 30 could easily be detached from base 10 to expose the used steel cannula 13.
A user is supposed to dispose of the steel cannula infusion set 1 in a sharps container designed for disposal of items that include a sharp needle, such as the infusion set 1 and syringes. However, a sharps container may not be readily available when a user wishes to dispose of and replace a used steel infusion set 1.
Accordingly, a need exists for an improved infusion set design and construction that can securely dispose of used steel needle infusion sets such that the steel cannula is not exposed, in order to protect people from such contact.